Process for the production of a fuse having a hollow channel

ABSTRACT

Process and apparatus for the production of a fuse having a cavity extending axially within the explosive core and being provided with a lining. The process includes the steps of continuously producing a casing at the lower end of the feed hopper, introducing an explosive from the feed hopper into the casing, passing the lining through the feed hopper while continuously winding filaments therearound in a helical manner for centrally guiding the lining through the feed hopper, and continuously introducing the lining together with the explosive into the casing at the end of the feed hopper. The apparatus includes a draw-off mechanism arranged vertically above the feed hopper, and one or more supply bobbins for the filaments can be provided as well as a bobbin for a tracer thread.

Ellie 1* States Patent [I91 1 3,7 24,318 Rohde et al. 451 Apr. 3, 1973[541 PROCESS FOR THE PRODUCTION OF 1,023,142 4 1912 Ellsworth..'.'.:......86/22 A FUSE. HAVING A HOLLOW CHANNEL PrimaryExaminer-Ben'amin A. Borchelt A 'E H J ldT d I v ssistant xamineraro uor [75] Inventors m ig gggg} 3:22;) Heltgen Att0meyCraig, Antonelli,Stewart & Hill [73] Assignee: Dynamit Nobel Aktiengesellschaft,- [57]ABSTRACT Trolsdorfc'ermany Process and apparatus for the production of afuse [22] Filed: Dec.'3, 1970- having a cavity extending axially withinthe explosive core and being provided with a lining. The process in-[21] Appl 94842 eludes the steps of continuously producing a casing at Ithe lower end of the feed hopper, introducing an ex- [30] ForeignApplication Priority Data plosive from the feed hopper into the casing,passing the lining through the feed hopper while continuously Dec. 3,1969 Germany ..P i9 60 569.7 winding filaments therearound in a helicalmanner for centrally guiding the lining through the feed hopper, lll andcontinuously introducing the lining together h [58] Fieid 57/7 8 theexplosive into the casing at the end of the feed hopper. The apparatusincludes a draw-off mechanism arranged vertically above the feed hopper,and one or [56] References cued more supply bobbins for the filamentscan be provided UNITED STATES PATENTS as well as a bobbin for a tracerthread.

3,381,568 5/1968 Kelly et al ..86/1 R 15 Claims, 2 Drawing FiguresPATENTEDAPR 3 I973 SHEET 1 BF 2 INVENTORS WILHELM ROHDE WERNER HELFGENBY o a ANLQL ATTORNEYS PROCESS FOR THE PRODUCTION OF A FUSE HAVING AHOLLOW CHANNEL BACKGROUND OF THE INVENTION The present invention relatesto a process and apparatus for the production of a fuse having a cavityextending axially within the explosive core and being provided with alining.

As is known, fuses serve for the transmission of detonations to fartherremote detonable systems. These fuses usually have a continuousexplosive core in a casing, the so-called sheath, for transmitting theinitiating impulse, wherein a corresponding propagation velocity of theinitiating impulse results depending on the type of explosive employedand the compression thereof.

It has now been found that the detonation velocity of a fuse having acavity which extends within the explosive core over the entire axiallength of the fuse and which is provided with a lining, e.g., a hose, atube, or the like, is substantially increased.

SUMMARY OF THE INVENTION It is the object of the present invention toprovide an economical process by means of which an axially extendingcavity can be incorporated into a fuse. In this connection, the presentinvention starts with a continuous process for the production of fuseswherein the explosive is introduced from a feeding hopper into a casingwhich is continuously manufactured at the lower end of the hopper.

In accordance with the present invention, the lining forming the hollowspace is guided through the feeding hopper and is continuouslyintroduced, together with the explosive, into the casing at the end ofthe feeding hopper. The continuous axial cavity created in this mannerwithin the explosive core results, depending on the conditions, in amore or less strong increase in the detonation velocity of thethus-manufactured fuse.

For the quality of the fuse to be produced, the position assumed by thelining such as, for example, a thermoplastic synthetic hose ofpolyethylene, within the explosive core is important. Optimum increasesin the detonation velocity of the fuse are obtained in case the liningis disposed centrally within the explosive core. Any deviation from thecenter of the explosive core, any change in the cross-sectional shape,e.g., by indenting the wall, impair the desired increase in detonationvelocity to a greater or lesser extent. Therefore, according to afurther feature of the process of the present invention, it is suggestedto wind two or more filaments helically about the lining to surround thelining in the manner of windings, and to guide the lining by means ofthe filaments centrally through the feeding hopper. Thus, the positionof the lining, e.g., a tube, is fixed and centered in the explosive coreby means of the filaments; besides, the filaments prevent any undesiredindentations in the tube wall and deformations, which can occur inunfavorable instances.

According to a further feature of the present invention, the filamentssimultaneously serve as carrier threads for the explosive trickling intothe fuse from the feeding hopper. For this purpose, the filaments areroughened on their surface and are pulled off a storage coil undertension and guided through the feeding hopper. Especially suitable arefilaments twisted from short fibers, e.g., from rayon staple orcellulose-base fiber, fully synthetic or mixed cellulose-base fiber,wool, flax, or the like. With the aid of such filaments, it is possible,in particular, to promote and facilitate the introduction of therequired amount of explosive for the manufacture of fuses having highexplosive weights or having a very fine-grained explosive powder. At thesame time, the detonation velocity of the fuse is substantiallyincreased by the introduction, according to the present invention, of alining forming a cavity.

In order to conduct the process of the present invention, i.e., theintroduction of, for example, an endless tube, into the explosive coreof a fuse, an apparatus is provided characterized in that a mechanicaldrawoff device is arranged vertically above the feeding hopper for thelining which is wound on a reel and for the supply coil of thefilaments. On this draw-off device, one or more supply reels for thefilaments can be provided, as well as for a so-called tracer thread forthe fuse. In a particularly advantageous manner, the supply reel for thefilaments is equipped with a double-thread cross winding and a hollowcore and is fixedly arranged centrally above the feeding hopper. Asimple ring winding is sufficient for the lining.

In order to guide the two filaments of the crosswound bobbin, arotatable bow or bracket with opposed eyes is mounted in the zone of thecross-wound reel, so that the bow is set into rotaty motion and thethreads are placed helically around the lining by the drawing-off of thefilaments. The lining taken off from the reel is guided into the feedinghopper through the hollow core of the stationary cross-wound bobbin.Suitably, the cross-wound bobbin is disposed in the longitudinal axis ofthe feeding hopper, so that the lining enters the feeding hopper throughthe longitudinal axis.

A special advantage of the apparatus in accordance with the presentinvention resides in that the feed of the filaments and of the lining iseffected without additional drive elements, solely on the basis of theremoval of the continuously manufactured fuse, whereby structuralsimplicity of the apparatus is made possible.

However, other devices for conducting the process of the presentinvention are also possible such as, for example, a construction whereina rotatable disk is horizontally arranged between the rolls, for thefilaments and the lining, and the upper opening of the feeding hopper.The filament bobbins are disposed vertically on the disk, and eyes aredisposed symmetrically at the periphery of the disk to guide thefilaments.

BRIEF DESCRIPTION OF THE DRAWING These and further features, objects andadvantages of the present invention will become more apparent from thefollowing description when taken in conjunction with the accompanyingdrawing which shows, for purposes of illustration only, an embodiment inaccordance with the present invention and wherein:

FIG. 1 is a cross-sectional view of the schematic progression of theprocess for the manufacture of a fuse in accordance with the presentinvention; and

FIG. 2 is an elevational view of a device for conducting the process ofFIG. 1.

DETAILED DESCRIPTION OF THE DRAWING Referring now to the drawing and, inparticular, to FIG. 1, a fuse having a hollow tube 13 axially extendingwithin the explosive core is manufactured by means of spinning machines16 (not shown in detail) which continuously produce the casing or sheath17 around the explosive 2 trickling out of the feeding hopper 1, theexplosive being surrounded by a strip 20 or the like, show in dashedline. The explosive 2 passes through gate 19 and forms the explosivecore 15. The hollow tube 13 and the filaments 4i and centering andfixing this tube in position pass, symmetrically to the longitudinalaxis 18, through the feeding hopper 1 filled with explosive 2. In thezone of the outlet of the feeding hopper 1, the filaments 4 and 5, whichmove in a rotary motion through the feeding hopper, are placed helicallyaround the hose 13.

FIG. 2 shows schematically the draw-off device by means of which thetube or hose 13 is introduced into the continuously manufactured fuse.Above the feeding hopper 1, which is filled with explosive 2, thecrosswound bobbin 3 is fixedly arranged by mounting means 7 with thehollow core 6 of this bobbin being disposed in the longitudinal axis 18of the feeding hopper 1, which axis simultaneously constitutes thelongitudinal axis of the fuse to be manufactured.

The two filaments 4 and 5 drawn off from the crosswound bobbin 3 areguided through opposed eyes 9 of the rotatably mounted bow 8. By thecontinuous removal of the fuse manufactured at the outlet of the feedinghopper and thus the removal of filaments 4 and 5 from the fixedlydisposed cross-wound bobbin 3, the filaments 4, 5 together with the bow8 enter into a circularly rotating motion 10 about the longitudinal axis18. The tube or hose 13 is provided on the reel 11 above the cross-woundbobbin and is guided in a centered position through the hollow core 6into the feeding hopper 1. Furthermore, the tracer or identifying thread14 of the fuse can be drawn off from the additional roll 12 arrangedabove the draw-off device and can be introduced into the fuse to beproduced through the hollow core 6 of the cross-wound bobbin 3 andthrough the feeding hopper ll.

By means of this device, several problems in the manufacture of a fusehaving an internal continuous cavity for increasing the detonationvelocity are simultaneously solved in a simple manner. Firstly,'the hoseforming the cavity is fed to the spinning machines in a centered mannerthrough the hollow core of the crosswound bobbin and through the feedinghopper. Furthermore, the hose is fixed by the filaments woundtherearound and is simultaneously protected against lateral identation.The filaments also serve as carrier threads for the explosive 2, sincethey continuously intersect a cone into the feeding hopper and thus takecare of a constant, uniform feed of the explosive. This is particularlytrue in case of a very fine, dust-like explosive which does not have aninherent fluidity.

Hoses of high-strength and of flexible plastic, e.g., polyolefins, suchas polyethylene or polypropylene are suitable as a lining for the cavitywithin the explosive core. However, other flexible materials, e.g.,textiles, are likewise usable. The process of the present invention,however, is not only suitable in conjunction with fuses and the casingthereof produced according to the spinning method, but can also beemployed for fuses, wherein the casings are manufactured according todifferent processes.

While we have shown and described an embodiment in accordance with thepresent invention, it is to be clearly understood that the same issusceptible of numerous changes and modifications as will be apparent toa person skilled in the art. We, therefore, do not wish to be limited tothe details shown and described herein, but intend to cover all suchchanges and modifications as are encompassed by the scope of the presentinvention.

We claim:

1. Process for the production of a fuse having an explosive core with anaxially extending cavity provided with a lining, comprising:

continuously producing a casing at the lower end of a feed hopper;

introducing an explosive from the feed hopper into the casing;

passing the lining through the feed hopper;

rotating at least two filaments so as to be helically wound around thelining;

centrally guiding the lining through the feed hopper by means of thefilaments; and

simultaneously introducing the lining having the filaments wound thereontogether with the explosive into the casing at the end of the feedhopper to form a lined axially extending cavity within the explosive.

2. Process according to claim 1, wherein the filaments have a roughenedsurface for aiding the introduction of the explosive into the casing.

3. Process according to claim 1, including drawing off of the filamentsfrom a supply reel under tension.

4. Process according to claim 3, wherein the filaments have a roughenedsurface for aiding the introduction of the explosive into the casing.

5. Process according to claim 1, wherein the filaments are twisted fromshort fibers.

6. Process according to claim 5, wherein the short fibers are selectedfrom the group consisting of rayon staple, fully synthetic or mixedrayon staple, wool or flax.

7. Process according to claim 5, wherein the filaments have a roughenedsurface for aiding the introduction of the explosive into the casing.

8. Process according to claim 7, including drawing off of the filamentsfrom a supply reel under tension.

9. Apparatus for the production of a fuse having an explosive coreprovided with a lined axially extending cavity, comprising feed hoppermeans for feeding explosive material into a casing of the fuse; reelmeans located vertically above the feed hopper means for supplying thelining for forming the axially extending cavity which is reeled upthereupon; bobbin means for the supply of filaments to be wound aboutthe lining also located vertically above the feed hopper means; anddraw-off means for the lining on the reel means and the filaments on thebobbin means.

10. Apparatus according to claim 9, wherein the supply bobbin means hasa double-thread cross winding and a hollow core, and the supply bobbinmeans is fixedly arranged centrally above the feed hopper means.

11. Apparatus according to claim 10, characterized in that at least twofilaments are supplied, and rotatable bow means being provided forguiding the at least two filaments, wherein the rotatable bow means hasopposed eyes and is mounted in proximity to the supply bobbin means.

14. Apparatus according to claim 9, wherein rotatable disk means ishorizontally located between the reel means and supply bobbin means andthe upper opening of the feed hopper means.

15. Apparatus according to claim 14, wherein the supply bobbin means arelocated vertically on the disk means, and eyes are symmetricallyprovided at the periphery of the disk means for guiding the filaments.

1. Process for the production of a fuse having an explosive core with anaxially extending cavity provided with a lining, comprising:continuously producing a casing at the lower end of a feed hopper;introducing an explosive from the feeD hopper into the casing; passingthe lining through the feed hopper; rotating at least two filaments soas to be helically wound around the lining; centrally guiding the liningthrough the feed hopper by means of the filaments; and simultaneouslyintroducing the lining having the filaments wound thereon together withthe explosive into the casing at the end of the feed hopper to form alined axially extending cavity within the explosive.
 2. Processaccording to claim 1, wherein the filaments have a roughened surface foraiding the introduction of the explosive into the casing.
 3. Processaccording to claim 1, including drawing off of the filaments from asupply reel under tension.
 4. Process according to claim 3, wherein thefilaments have a roughened surface for aiding the introduction of theexplosive into the casing.
 5. Process according to claim 1, wherein thefilaments are twisted from short fibers.
 6. Process according to claim5, wherein the short fibers are selected from the group consisting ofrayon staple, fully synthetic or mixed rayon staple, wool or flax. 7.Process according to claim 5, wherein the filaments have a roughenedsurface for aiding the introduction of the explosive into the casing. 8.Process according to claim 7, including drawing off of the filamentsfrom a supply reel under tension.
 9. Apparatus for the production of afuse having an explosive core provided with a lined axially extendingcavity, comprising feed hopper means for feeding explosive material intoa casing of the fuse; reel means located vertically above the feedhopper means for supplying the lining for forming the axially extendingcavity which is reeled up thereupon; bobbin means for the supply offilaments to be wound about the lining also located vertically above thefeed hopper means; and draw-off means for the lining on the reel meansand the filaments on the bobbin means.
 10. Apparatus according to claim9, wherein the supply bobbin means has a double-thread cross winding anda hollow core, and the supply bobbin means is fixedly arranged centrallyabove the feed hopper means.
 11. Apparatus according to claim 10,characterized in that at least two filaments are supplied, and rotatablebow means being provided for guiding the at least two filaments, whereinthe rotatable bow means has opposed eyes and is mounted in proximity tothe supply bobbin means.
 12. Apparatus according to claim 10, whereinthe lining reel means is disposed above the supply bobbin means forsupplying the lining to the feed hopper means through the hollow core ofthe supply bobbin means.
 13. Apparatus according to claim 12,characterized in that at least two filaments are supplied, and rotatablebow means being provided for guiding the at least two filaments, whereinthe rotatable bow means has opposed eyes and is mounted in proximity tothe supply bobbin means.
 14. Apparatus according to claim 9, whereinrotatable disk means is horizontally located between the reel means andsupply bobbin means and the upper opening of the feed hopper means. 15.Apparatus according to claim 14, wherein the supply bobbin means arelocated vertically on the disk means, and eyes are symmetricallyprovided at the periphery of the disk means for guiding the filaments.